A triangle has side lengths measuring [tex]$3x$[/tex] cm, [tex]$7x$[/tex] cm, and [tex]$h$[/tex] cm. Which expression describes the possible values of [tex]$h$[/tex] in cm?

A. [tex]$4x \ \textless \ h \ \textless \ 10x$[/tex]
B. [tex]$10x \ \textless \ h \ \textless \ 4x$[/tex]
C. [tex]$h = 4x$[/tex]
D. [tex]$h = 10x$[/tex]



Answer :

In order to determine the possible values for \( h \) given a triangle with side lengths \( 3x \) cm, \( 7x \) cm, and \( h \) cm, we need to use the triangle inequality theorem. This theorem states that the sum of the lengths of any two sides of a triangle must be greater than the length of the third side.

Thus, for our triangle:

1. \( 3x + 7x > h \)
2. \( 3x + h > 7x \)
3. \( 7x + h > 3x \)

Let's solve these inequalities one by one:

1. \( 3x + 7x > h \)
[tex]\[ 10x > h \][/tex]
[tex]\[ h < 10x \][/tex]

2. \( 3x + h > 7x \)
[tex]\[ h > 7x - 3x \][/tex]
[tex]\[ h > 4x \][/tex]

3. \( 7x + h > 3x \)
[tex]\[ 7x + h > 3x \][/tex]
[tex]\[ h > 3x - 7x \][/tex]
[tex]\[ h > -4x \][/tex]

However, the inequality \( h > -4x \) is redundant because \( h > 4x \) is already a stricter condition given that \( x \) is positive.

Combining the first two relevant inequalities, we get:
[tex]\[ 4x < h < 10x \][/tex]

Thus, the expression that describes the possible values of \( h \) is:
[tex]\[ 4x < h < 10x \][/tex]

So, the correct answer is:
[tex]\[ \boxed{4x < h < 10x} \][/tex]

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